Horrible engine noise started right before Thanksgiving of 2020. It sounded like loose little rocks underneath, then a metallic sound like spark knocking. After doing some research and not being able to identify the problem, especially since the noise would be noticeable at times, I was able to get a good mechanic to drive and listen to it and he said to put premium gas.

After that, I kept researching and found out that that noise is known as engine detonation. The easy fix is definitely putting premium gas only, and this is because of some carbon deposits in the fuel injectors and hoses that regular gas produces. Hyundai says to put 87 or higher gas, but their GDI technology wasn't well designed to burn regular gas properly.

Thank God that annoying noise is gone now, at least for the time being.

I have taken this car to the dealership quite a few times was told that Hyundai know about the noise and there is nothing that can be done until the dealership is notified from corporate . The noise is annoying when you start car it excellerates and then decelerates but the noise is still there on open road it gets louder the more you accelerates. I am not happy with this car . I have had 3 Hyundai no problems but this one is not acceptable . I have leased this car and I am to the point of getting something else and it won't be a Hyundai. NO One wants to fix the problem was told it is the foam over the fuel pump sometimes it is so loud it turns heads . I am not happy at all with this car